Add Android APK fleet nodes with Crucible UI integration and tests.

APK wrapper registers platform=android via AETHERFORGE_PLATFORM; fleet UI shows robot icons, Android Access Depth probes, and a shortened mining onion timeline.

agent/client/protocol_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"testing"
 
+	"crypto-miner-agent/config"
 	"crypto-miner-agent/job"
 )
 
@@ -45,6 +46,19 @@ func TestAuthPayloadJSONRoundTrip(t *testing.T) {
 	}
 }
 
+func TestAuthPayloadPlatformFromEnv(t *testing.T) {
+	t.Setenv("AETHERFORGE_PLATFORM", "android")
+	if got := config.RegistrationPlatform(); got != "android" {
+		t.Fatalf("RegistrationPlatform() = %q want android", got)
+	}
+	in := AuthPayload{Platform: config.RegistrationPlatform(), Arch: "arm64"}
+	var out AuthPayload
+	roundTrip(t, in, &out)
+	if out.Platform != "android" {
+		t.Fatalf("auth platform = %q want android", out.Platform)
+	}
+}
+
 func TestAuthResponseJSONRoundTrip(t *testing.T) {
 	in := AuthResponse{Success: true, AgentID: "a1", Error: ""}
 	var out AuthResponse